if you want to maintain the exact words:
من خدایی که مرا (=من را) به زندگی آورد را قسم (می) دادم
من خدایی که برای من زندگی آورد را قسم (می) دادم
Although they are both semantically and grammatically correct, but you better use IMANAKBARI's sentences.
I'm not sure about the place of red را whether it is better to be after خدایی or where it is now.
Besides, what is the tense of the sentence:
I swear (قسم می دهم)
I swore (قسم دادم)
I was swearing (قسم می دادم)